Solid electrolytic capacitors (e.g., tantalum capacitors) have been a major contributor to the miniaturization of electronic circuits and have made possible the application of such circuits in extreme environments. Conventional solid electrolytic capacitors may be formed by pressing a metal powder (e.g., tantalum) around a metal lead wire, sintering the pressed part, anodizing the sintered anode, and thereafter applying a solid electrolyte. Intrinsically conductive polymers are often employed as the solid electrolyte due to their advantageous low equivalent series resistance (“ESR”) and “non-burning/non-ignition” failure mode. Such electrolytes can be formed through in situ polymerization of the monomer in the presence of a catalyst and dopant. Alternative, premade conductive polymer slurries may also be employed. Regardless of how they are formed, one problem with conductive polymer electrolytes is that it is difficult for such polymers to penetrate and uniformly coat the pores of the anode. Not only does this reduce the points of contact between the electrolyte and dielectric, but it can also cause facilitate delamination of the polymer from the dielectric during mounting or use. As a result of these problems, it is often difficult to achieve ultralow ESR and/or leakage current values in conventional conductive polymer capacitors. The problems are compounded when the valve metal powder used to form the anode has a high specific charge (e.g., about 70,000 microFarads*Volts per gram (“μF*V/g”) or more), which is desired for achieving high capacitance values. Such high “CV/g” powders are generally formed from particles having a small size and large surface area, which results in the formation of small pores between the particles that are even more difficult to impregnate with the conductive polymer.
As such, a need currently exists for an improved electrolytic capacitor containing a conductive polymer solid electrolyte.